<form name="form" class="form-horizontal">
<div class="control-group" ng-class="{error: form.Todo.$invalid}">
    <label class="control-label" for="Todo">Todo</label>
    <div class="controls">
        <input type="text" ng-model="item.Todo" id="Todo">
    </div>
</div>
<div class="form-actions">
    <button class="btn btn-primary">
        Submit
    </button>
    <a href="#/" class="btn">Cancel</a>
</div>
</form>